Accordion keyboard controlled accompanimental tone generator



March 26, 1968 5. J. CARRAS 3,375,320

ACCORDION KEYBOARD CONTROLLED ACCOMPANIMENTAL TONE GENERATOR 5 Sheets-Sheet 1 Filed Feb. 23, 1965 INVENTOR GEORGE d. CARRAS ATTORNEY March 26, 1968 G. J. CARRAS ACCORDION KEYBOARD CONTROLLED ACCOMPANIMENIAL TONE GENERATOR 5 Sheets-Sheet 2 Filed Feb. 23, 1965 m m m ATTORNEY ACCORDION KEYBOARD CONTROLLED ACCOMPANIMENTAL TONE GE NNNNN OR eeeeeeeeeeee 64 5 Sheets-Sheet 5 G. J. CARRAS ACCORDION KEYBOARD CONTROLLED ACCOMPANIMENTAL TONE GENERATOR 1965 id/Wk March 26, 1968 Fild Feb. 23,

ATTORNEYS United States Patent 0 3,375,320 ACCORDION KEYBOARD CONTROLLED ACCOM- PANIMENTAL TONE GENERATOR George J. Carras, 622 Avery St., Parkersburg, W. Va. 26101 Continuation-impart of application Ser. No. 291,396,

June 28, 1963. This application Feb. 23, 1965, Ser.

7 Claims. (Cl. 84-1.04)

ABSTRACT OF THE DISCLOSURE An attachment for an accordion, said accordion comprising a keyboard having a plurality of keys, and an individual valve associated with each key, depression of a particular key causing operation of its associated valve to cause the sounding of a predetermined note corresponding to said particular key, said attachment comprising a plurality of individual electrical contact means each operatively associated with one of the keys of said keyboard within a predetermined range comprising a plurality of contiguous octaves, a plurality of resistors connected to said contact means to produce an eifective resistance, the magnitude of which is controlled by said contact means, electrically controllable tone generating means, said tone generating means comprising a pitch control circuit connected :for response to said effective resistance, said tone generating means producing a tone the pitch of which is determined by the magnitude of said effective resistance, said pitch corresponding to the note produced by said accordion in response to the depression of said particular key, and loudspeaker means connected to said tone generating means for acoustically reproducing a note corresponding to said predetermined tone to accompany said note sounded by said accordion.

This application is a continuation-in-part of my copending application Ser. No. 291,396 filed on June 28, 1963, and now abandoned.

The present invention relates to electrical tone generator which is con-trolled by the usual keyboard of an accordion during the course of the normal playing of the accordion to provide an instrumental accompaniment.

The invention advantageously utilizes a tone generator commercially known as a Clavioline and which is the subject matter of US. Patent No. 2,563,477 issued to Constant Martin.

In a modified embodiment, the invention utilizes a set of accordion keyboard operated switches for controlling the Clavioline tone generator. Adjustable mounting means are provided which make the supplementary switches readily adaptable to a wide range of commercial- 'ly available accordions without any need for significant structural modifications of the particular accordion,

The usual Clavioline comprises a vacuum tube oscillator controlled by a three octave keyboard which is arranged to be mounted slightly below and in front of the keyboard of a piano. The pianist plays the normal bass passages with his left hand on the piano keyboard. The melody, which is usually played with the right hand, may be played on the keyboard of the Cl'avioline or on the piano keyboard, as desired.

The Cl-avioline produces only a single note which is audible ,by means of a loudspeaker. If two or more keys are pressed simultaneously, only the highest note will be produced. Control switches are provided which permit the tone quality of the note to be varied over a wide range of wave shapes and clamping effects to simulate stringed instruments, 'WOOdWlIldS, brass and various org-an voices, including instruments such as the Hawaiian guitar, banjo,

zither and bagpipes. The detailed circuitry of the tone generator portion of the Clavioline is utilized in accordance with the present invention to obtain a directly controlled instrumental accompaniment to the playing of an accordion.

Instead of using the usual separate Clavioline keyboard which is placed adjacent to the piano keyboard, a series of contacts is mounted under the grille of the accordion together with a series of resistors. The depression of an accordion key to open its associated valve simultaneously changes the resistance connected in the pitch control circuit of the Clavioline so that the corresponding instrumental note is sounded by the Clavioline simultaneously with the (reed) note produced by the accordion. The tone quality and timbre of the Clavioline note is adjusted to simulate a particular instrument in the usual manner by switches similar to organ stops operatively associated with the tone generator.

The three octave range of the pitch control resistor circuit may be selectively raised or lowered by one octave by means of a three position switch which advantageously forms an integral part of a foot-operated control unit which includes the volume control pedal.

The invention will be better understood upon reading the following specification with reference to the accompanying drawing forming a part hereof.

Referring to the drawing: FIGURE 1 is an exploded perspective view of an accordion showing the grille partially removed and the -key actuated pitch control cont-act and resistor unit partially removed.

FIGURE 2 is a perspective view of the accordion of FIG. 1, partly broken away to illustrate details of construction.

FIGURE 3 is an enlarged transverse sectional view taken along the line 3-3 of FIG. 2, looking in the direction of the arrows.

FIGURE 4 is an enlarged side elevational view showing one of the accordion keys and its associated resistor and contacts the key being shown in its normal position, its depressed position being indicated in dotted lines.

FIGURE 5 is a fragmentary perspective view showing a valve control pad and a portion of the connecting member which extends to its associated key together with the contacts which are actuated by the connecting member upon depression of the key. FIGURE 6 is a schematic circuit diagram.

FIGURE 7 is a fragmentary circuit diagram showing the wiring of representative sets of contacts and their associated resistors.

FIGURE 8 is a perspective view of an accordion equipped with an adjustably mounted switch unit in accordance with a modified embodiment of the invention. FIFIGURE 9 is an end view of the accordion shown in FIGURE 10 is a plan view of the accordion keyboard of FIG. 8 with the shielding cover for the electrical contacts removed.

FIGURE 11 is an enlarged transverse sectional view taken along the line 11-11 of FIG. 10 looking in the direction of the arrows with the accordion key in its non-operated position.

FIGURE 12 is a view similar to FIG. 11 showing the accordion key in its operated or depressed position. i Referirng to FIG. 1, an accordion designated gene-rally as 10 comprises the usual bellows 11 and a piano type keyboard 12. The keyboard 12, as shown, has a range of approximately five octaves provided by a total of substantially forty individual keys. Directly above the keyboard 12 is a louvered grille 14 which encloses the valves actuated by the keyboard 12.

Associated with each individual key 15 (FIG. 4) is a valve member or control pad 16 which normally closes an aperture (not shown) in a valve plate 18. The key 15 is pivoted intermediate its ends to a pivot rod 19 fixed to the frame of the keyboard portion of the accordion 10. The valve member 16 is connected to the key 15 by a rigid connecting rod 20. Pressure exerted on the key 15 will displace the key 15 and the valve member 20 to the dotted line position shown in FIG. 4 in which the valve member 16 is raised so that the particular note associated with the individual key 15 will be sounded bythe accordion in the usual manner. If a plurality of keys are pressed, all of the accordion notes will be sounded simultaneously so that chords may be obtained.

A barrel-shapedsleeve 22 is mounted on each connecting rod 20 between the valve member 16 and the key 15. A spring (not shown) under key is operatively associated with the connecting rod and yieldingly urges the valve member .16 into its closed position so that the outward flow of air through its associated reed is normally prevented.

The attachment of the present invention comprises a supporting bridge structure 25 consisting of a mounting plate 26 carried by' end brackets 27 and 28 secured to the frame of the keyboard 12. The pitch control circuit of the Clavioline has a range of three octaves.

Accordingly, thirty-six sets of control contacts 30-01 through 30-36 are mounted on the mounting plate 26. Associated with each set of control contacts 30-01 through 30-36 is a corresponding fixedprecision resistor 31-01 through 31-36. Each set of control contacts 30' comprises a pileup of insulating members 33, a long leaf type contact spring 34, a medium length contact spring 35 and a short contact spring 36. Each contact assembly pileup is secured to the underside of the mounting plate 26 by screws 38.

The long contact spring 34 is gently tensioned to bear yieldingly and continuously against the external surface of its associated barrel-shaped sleeve member 22 without any spacing which might produce an objectionable acoustic click upon mechanical contact between the free end of the long spring 34 and its associated barrel-shaped sleeve 22 during the course of depression of the corresponding key 15.

In FIG. 3, a transversely extending channel member 39 supports a plurality of microphones 40 positioned behind the grille 14. Only a single one of the microphones. 40 is visible in the drawing. The microphones 40 are suitably interconnected to provide a common input for the amplifier and loudspeaker which are described in greater detail below. The microphones 40 include a plurality of separate microphones located for response to the treble reeds of the accordion in addition to one or more further microphones arranged for response to the bass reeds. Control knobs 42 are mounted on the shafts of potentiomete'rs 41. The potentiometers 41 are independently connected to control the tone or timbre of the bass and treble sections of the accordion and also the combined input level from the several microphones 40' associated with the bass and treble sections, respectively, which is supplied to the input of the amplifier and loudspeaker. One of the control knobs 42 operates a control for the vibrato or tremolo generator of a Clavioline which incorporates this feature. A suitable ON-OFF switch (not shown) is associated with one of the manually operable control knobs 42. The ON-OFF" switch selectively permits the accordion to, be played in the normal manner without any accompaniment and with or without the loudspeaker.

Referring to FIG. 5, the Clavioline portion of the instrument comprises a vibrato generator 44. Appropriate controls are provided, as by one or more of the stops to control the frequency and amplitude of the vibrato generator in accordance with the characteristics of the particular musical instrument which it is desired to simulate or other desired tonal effect.

The vibrato generator 44 is connected in conventional manner to vary the frequency of a tone generator 45 about its mean frequency. The tone generator 45 is connected to the vibrato generator 44 through a buffer stage 46. The tone generator 45 includes a pitch control circuit, one conductor 48 of which is grounded. The other conductor 49 of the pitch control circuit, when connected to ground through a circuit of precisely determined resistance, causes the tone generator 45 to oscillate at the frequency of the corresponding desire-d musical note. The completion of the circuit of predetermined resistance unblocks a resistance-capacitance oscillator within the Clavioline and causes it to oscillate at the desired frequency. Appropriate capacitance adjustments may be made by a trimmer capacitor (not shown) to obtain the proper pitch for a selected note such as A having a standard frequency of 440 cycles per second. The frequencies of the other notes are properly interrelated by the precision resistors 31-01 through 31-36 in conjunction with a calibration resistor (not shown). These details of circuitry are a part of the Clavioline with which the accordion of the present invention is used.

The output of the tone generator 45 is fed to the input of a normally blocked amplifier 50. A control conductor 52 extends to the amplifier 50. When the conductor 52 is grounded, the amplifier 50 gradually becomes operative at a rate determined by a delay network (not shown). When percussion effects are desired, the delay network is cut out by a switch so that the amplifier 50 becomes operative abruptly. The switch may be arranged to be controlled by one of the stops, if desired. The conductor 52 is grounded upon the depression of any key 15 by the short contact spring 36 in conjunction with the medium length spring 35 of the particular contact set 30-01 through 30-36. It several keys 15 are pressed simultaneously, only the minimum total series resistance of the resistors 31-01 through 31-36 will be effective to produce electrically the acoustic note determined by the key 15 of highestpitch which is then depressed.

The output of the amplifier and percussion injector 50 is connected through a filter 53 to a volume control potentiometer 54. The input of an amplifier 55 is connected to the volume control potentiometer 54 and its output is connected to a loudspeaker 57 for the acoustic reproduction of the note generated by the tone generator 45.

The volume control potentiometer 54 forms a partof a foot operated control unit designated generally as 58.

A volume control or expression pedal 59 is connected by linkage 61 to vary the position of the movable contact arm of the potentiometer 54 so that increased pressure on the pedal 59 increases the volume of sound deli'vered by the loudspeaker 57. Near the toe of the expression pedal 59 is a laterally displaceable foot actuable member 62 which controls a three position octave control switch 63. Within the tone generator 45 are capacitors (not shown) which may be connected and disconnected to shift the tonal range of the generator 45. The connections for the octave control capacitors extend to the contacts of LOW and HIGH relays and 66, respectively. With the operating windings of both relays 65 and 66 deenergized, the pitch of the tone generator is within the three octave normal range, the appropriate capacitance being connected through the normally closed contacts of HIGH relay 66. The operating windings of the relays 65 and 66 are both connected to a suitable grounded source of energizing potential designated Movement of the switch 63' to its LOW" position by lateral displacement of the foot-actuable member 62 energizes the operating Winding of the LOW relay Y65 and causes closure of its normally open contacts to introduce additional capacitance into the pitch control circuit of tone generator 45. This lowers its tonal range by one octave. By lateral displacement of the foot-actuable member 62 in the opposite direction of its HIGH position, the HIGH relay 66 is operated and a portion of the normal capacitance is disconnected to raise the tonal range of the tone generator 45 by one octave. The octave switch 63 thus extends the range of the tone generator 45 to five octaves as in the Clavioline.

Referring to FIG. 7, the grounded pitch control conductor 48 is connected in multiple to all of the longer contact springs 34. The pitch control resistors 31-01 through 31-36 are all connected in series and each junction between two adjacent resistors is connected to one of the medium length contact springs 35-02 through 35-36. The free end of the lowest pitch resistor 31-01 is connected to the medium length contact spring 35-01 of the lowest pitch contact set 30-01. The short springs 36-01 through 36-36 are all connected in multiple to the common control conductor 52 for the amplifier 50.

When a particular key 15 is depressed within the three octa've range, the valve 16 opens to cause the sounding of the corresponding accordion note. The long contact spring 34-n (n designating a particular key of the 36 keys) engages its associated medium length contact spring 35-n which starts the tone generator 45 with a pitch determined by the total series resistance of the resistors 31-11 through 31-36 for the particular key, 31-(n+1) through 31-36 for the next key, etc., the minimum resistance being that of resistor 31-36. The octave control switch 63 will, of course, raise or lower the pitch by one octave as desired. The medium length contact spring 35-11 for the particular key next engages its associated short contact spring 36-n to render the amplifier 50 operative.

In operation, the accordionist plays the instrument in the usual manner. When depressing any key within the range which controls the Clavioline, the Clavioline will simultaneously produce an accompanying instrumental note having a pitch which is determined by the highest accordion note, within the range, for which a key is depressed. The accompanying note may have a pitch which is raised or lowered by one octave by foot operation of the switch 63. The basic melody is ordinarily conveyed by the key of highest pitch so that the accordionist may play chords on the accordion while obtaining a single note accompaniment consisting of the melody which is produced by the loudspeaker 57. The melody may simulate an instrument entirely ditferent from the accordion such as a banjo, clarinet, flute, or horn, for example. The accordionist thus automatically obtains the effect of a two piece ensemble without any "additional effort on his part.

Referring to FIGS. 8 through 12, the accordion, designated generally as 70, is provided with a piano-type keyboard 71 formed by a series of keys 72. An output jack 74 is provided for convenient connection of the controls located in the accordion 70 to the circuitry shown in FIG. 6, as described above. A suitable multiconductor cable (not shown) is used in conventional manner. The pitch control resistors 31-01 through 31-36 are connected as previously described. Manually operable control knobs 42 are similarly mounted on a channel member 39.

The pitch control switches, designated generally as 75-01 through 75-36 in the embodiment illustrated in FIGS. 8-12, are all mounted externally of the accordion 70 and include a common spring supporting bar 76. The supporting bar 76 is mounted in end brackets 77 which provide for adjustment of the distance between the bar 76 and the keyboard 71 by means of set screws 78. The end brackets 77 are secured to the frame of the accordion 70 by screws 79 which are located on the frame of the accordion 70 adjacent to the lateral ends of the keyboard 71. All of the keys 72 of the keyboard 71 are mounted for individual pivotal movement on a common shaft or fixed pivot rod 80.

The supporting bar 76 carries panel 82 formed of insulating material. The panel 82 is connected to the supporting bar 76 by a plurality of mounting screws 83 disposed at spaced locations along the bar 76. Each screw 83 has a head 84 which engages the inner face of the panel 82. Each screw 83 passes through a tubular spacer 86 formed of insulating material and through the supporting bar 76. At its outer end, each screw 83 is provided with a nut 87.

There is a switch member 88 operatively associated with each of the keys 72 except for the five keys at the extreme right hand end of the keyboard 71. Additional pitch control switches could be provided for these five keys, if desired. All of the switch members 88 are mounted for individual pivotal movement on a common supporting rod 90. One end of rod 90 is secured to a mounting block 91 carried by the insulating panel 82. Intermediate its ends and at its left hand end as viewed in FIG. 10, the rod 90 is supported by a plurality of bracket members 92. A series of stiff helical compression springs 93 is arranged on the pivot rod 90.

Each of the switch members 88 is biased for clockwise rotation as viewed in FIGS. 11 and 12 by a helical compression spring. The ends of each spring 94 are seated in recesses 95 and 96 formed in the bar 76 and switch member 88, respectively. An actuating screw 98 is threaded into each of the switch members 88. At its lower end, each actuating screw 98 carries a threaded cap 99 formed of suitable plastic material. The cap 99 is continuously urged into yielding engagement with its associated key 72 outwardly of the pivot rod 80 by the action of its individual compression spring 94.

There is an individual contact member 100 associated with each of the contact members 88. Each contact member 100 consists of a tightly wound helical tension spring one end of which is fixedly mounted in the insulating panel 82, the other end being free. The fixed end of each contact spring 100 is connected to one of the resistors 31-01 through 31-36. Except in the case of resistor 31-01 the contact spring is connected to the junction between two serially connected resistors, as illustrated for contacts 35 in FIGS. 6 and 7. The grounded contacts 34 are constituted by the common supporting bar 76 and pivot rod 90 which are interconnected by the compression springs 94 with all of the switch members 88. There is a common contact bar 101 mounted on threaded studs 102 secured to the insulating panel 82. The contact bar 101 is connected to the amplifier 50 by a conductor such as 52 in the same manner as the contacts 36 described above.

Each of the switch members 88 carries an insert 103 formed of a suitable plastic material such as Teflon, for example. The insert 103 is held against rotation by the switch member 88 and the screw 98 passes through the insert 103 in tightly threaded engagement therewith. Each screw 98 may be turned to adjust the position of its cap 99 with respect to the key 72 and it will remain in the desired position of adjustment being frictionally held by the insert 103. Depression of any key will flex its associated contact spring 100 upwardly as shown in FIG. 12 thereby grounding both the spring 100 and the common contact bar 101. The operation is the same as that described above the contact members 34, 35 and 36. The switch members 88 and contact members 100 are enclosed by a guard or cover member 104 which is secured by screws 105 to mounting brackets 106.

While I have shown and described what I believe to be the best embodiments of my invention, it will be apparent to those skilled in the art that various changes and modifications may be made therein without departing from the spirit and scope of the invention as defined in the appended claims.

What is claimed is:

1. An accordion comprising a piano-type keyboard having a plurality of individual keys; a valve associated with each key; a plurality of connecting means each connecting one of said keys to its associated valve to cause said accordion to emit a musical note in response to the depression of any one of said keys, the pitch of said note corresponding to the particular key which is depressed; an apertured cover member extending over and enclosing all of said valves; a supporting member extending in proximity to said connecting means, said supporting member being enclosed by said cover member; a plurality of contact means carried by said supporting member, each of said contact means being operatively associated with one of said keys within a range of at least one octave, each of said contact means being actuable by one of. said connecting means upon the depression of the key which said connecting means connects to its associated valve; a plurality of resistors carried by said supporting means, each resistor being associated with one of said contact means; and circuit means interconnecting said contact means and said resistors to obtain a resistance the value of which is determined by key of highest pitch within said range which is then depressed.

2. An attachment for an accordion, said accordion comprising a keyboard having a plurality of keys, and an individual valve associated with each key, depression of a particular key causing operation of its associated valve to cause the sounding of a predetermined note corresponding to said particular key, said attachment comprising: a plurality of individual electrical contact means each operatively associated with one of the keys of said keyboard; a plurality of resistors connected to said contact means and mounted along the length of said keyboard to produce an eilective resistance the magnitude of which is controlled by said contact means; electrically controllable tone generating means, said tone generating means comprising a pitch control circuit connected for response to said eliective resistance, said tone generating means producing a tone the pitch of which is determined by the magnitude of said effective resistance, said pitch corresponding to the note produced by said accordion in response to the depression of said particular key; and loudspeaker means connected to said tone generating means for acoustically reproducing a note corresponding to said predetermined tone to accompany said note sounded by said accordion.

3. An attachment for an accordion, said accordion comprising: a series of tuned reeds having pitches comprised within a tonal range of a plurality of octaves; means for supplying air under pressureto said reeds; an individual control valve for each reed; and a series of self restoring keys arranged to form a piano-type keyboard, each of said keys being actuable to open a particular one of said valves whereby the note generated by the corresponding reed may be sounded, said attachment comprising: elongated supporting means extending transversely oi said keys inwardly of the manually operated portions thereof; a series of movable contact members carried by said supporting means, each movable contact member being mounted for pivotal movement and including an extension which engages one of said keys for causing pivotal movement of said contact member in response to operation of said key; resilient means biasing said movable contact member for maintaining said extension in yielding engagement with said key; a separate cooperating contact member for each movable contact member, all of said cooperating contact members being carried by said supporting means; starting contact means common to all of said contact members, actuation of one of said keys causing simultaneous engagement among one of said movable contact members, one of said cooperating contact members and said starting contact means; a group of serially connected resistors carried by said supporting means, said resistors being included in a pitch control circuit, said resistors being connected to said contact members to establish a particular value for the resistance of.

said pitch control circuit in response to the actuation of one of said keys; electrical tone generating means producing an output'voltage, said tone generating means ineluding pitch determining means connected for response to said pitch control circuit, said tone generating means being connected to said starting contact means for operation in response to the actuation of any one of said keys; and loudspeaker means connected for response to said output voltage.

4. An attachment according to claim 3, further comprising amplifier means having an output connected to said loadspeaker means and microphone means connected to the input of said amplifier means, said microphone means being positioned for acoustic response to said reeds,

5. An attachment according to claim 3, wherein said supporting means comprises a common pivot rod on which all of said movable contact members are mounted, said attachment further comprising a series of helical compression springs coaxially mounted on said pivot rod for maintaining said movable contact members located in predetermined positions longitudinally of said pivot rod.

6. An attachment for an accordion, said accordion comprising a keyboard having a plurality of keys and an individual valve associated with each key, the depression of a particular key causing operation of its associated valve to cause the sounding of a predetermined note cor-. responding to said particular key, said attachment comprising a plurality of individual electrical contact means each operatively associated with one of the keys of said keyboard within a predetermined range of at least one octave, individual circuit means, each controlled by one of said contact means, electrically controllable tone gener ating means selectively responsive to all of said circuit means, said tone generating means producing a predetermined tone the pitch of which corresponds to the note produced by said accordion in response to the depression of said particular key, loudspeaker means connected to, said tone generating means for acoustically reproducing a note corresponding to said predetermined tone to accompany said note sounded by said accordion, foot-controllable pedal means, volume control means connected,

to control the acoustic output of said loud-speaker means, said volume control means being responsive to the depression of said pedal means, fo0t-actuatable contact means positioned in proximity to said pedal means for actuation by lateral displacement of the foot, and octave changing means included in said tone generating means, said octave changing means being connected to said foot-actuatable contact means for changing the pitch of each tone generated by said tone generating means.

7. An attachment for an accordion, said accordion comprising a keyboard having a plurality of keys and an individual valve associated with each key, the depression of a particular key causing operationv of its associated valve to cause the sounding of a predetermined note corresponding to said particular key, said attachment comprising a plurality of individual electrical contact means each operatively associated with one of the keys of said keyboard, a'plurality of resistors connected to said contact means to produce an effective resistance'the magnitude of which is controlled by said contact means, elec-. trically controllable tone generating means, said tone generating means comprising a pitch control circuit connected for response to said effective resistance, said tone generating means producing a tone the pitch of which is determined by the magnitude of said effective resistance, said pitch corresponding to the note produced by said accordion in response to the depression of said particular key, loudspeaker means connected to said tone generating means for acoustically reproducing a note corresponding to said predetermined tone to accompany said notegenerating means, said octave changing means being connected to said foot-actuatable contact means for changing the pitch of each tone generated by said tone generating means by one octave.

References Cited UNITED STATES PATENTS Martin 84-1.27 Terlinde 841.14 Carlson 84171 Hess 84376 Donahue 84-1.16 Borell 84-376 ARTHUR GAUSS, Primary Examiner.

B. P. DAVIS, Assistant Examiner. 

